DESCRIPTION: (Applicant's Description) Kaposi s sarcoma associated herpes virus/human herpesvirus 8 (HHV-8) is found in Kaposi's sarcoma (KS) and primary effusion lymphomas (PEL). The applicant has the largest collection of frozen PEL samples and their DNA and RNA. Also, he has established an EBV-negative, PEL cell line (KS-1) that produces large quantities of HHV-8 which can actively infect other cells. Armed with these tools, the applicant will: 1) determine the spectrum of HHV-8-related disorders and determine which hematopoietic cells are permissive for HHV-8 infection. The tissue bank of 3,800 lymphoproliferative disorders, of which 722 are from HIV-infected individuals, will allow him to determine which disorders contain HHV-8 sequences. Also, the hematopoietic cell types permissive for HHV-8 infection will be determined, including macrophages and dendritic cells. 2) Identify and study cytokines produced by HHV-8-infected lymphocytes and determine the effect of cytokines and other agents on growth of HHV-8 infected cells. Using the KS-1 cell line and matched HHV-8 infected lymphoma lines, the applicant will determine cytokines produced by the cells and identify cytokines that stimulate growth of the cells and determine if autocrine loops exist. 3) Define the modulation of HHV-8 expression in lymphoid cells, especially from open reading frame-72 (ORF-72, cylin D-like homolog) and correlate these results with their modulation of growth and apoptosis. The applicant s KS-1 and other HHV-8 infected lymphoma cell lines will be exposed to active compounds and their expression of ORF-72, -73, -74, -75 can be correlated with their alterations in clonal growth, apoptosis and apoptosis-related proteins. Additional studies of ORF-72 will determine its protein partners, kinase activity, and ability to deregulate the cell cycle. Selective molecular biology studies will also be performed on PEL cells: A) determine their cytogenetic abnormalities, B) examine for their alterations of selected tumor suppressor genes, and C) perform allelotyping of PEL to determine DNA regions that contain altered tumor suppressor genes. In summary, the unique cell line, its ability to infect other cells and the large tumor bank will allow in-depth analysis of HHV-8 related lymphomas.